Ex Parte Cheng et al

Patent Trial and Appeal BoardAug 9, 2013

11688692 (P.T.A.B. Aug. 9, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 11/688,692 03/20/2007 Yi-Kan Cheng 2006-0379 / 24061.799 1505 42717 7590 08/09/2013 HAYNES AND BOONE, LLP IP Section 2323 Victory Avenue Suite 700 Dallas, TX 75219 EXAMINER NGUYEN, NHA T ART UNIT PAPER NUMBER 2825 MAIL DATE DELIVERY MODE 08/09/2013 PAPER Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ____________________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________________ Ex parte YI-KAN CHENG, KE-YING SU, and VICTOR C. Y. CHANG ____________________ Appeal 2010-011760 Application 11/688,692 Technology Center 2800 ____________________ Before ALLEN R. MacDONALD, MICHAEL J. STRAUSS, and HUNG H. BUI, Administrative Patent Judges. BUI, Administrative Patent Judge. DECISION ON APPEAL Appellants1 seek our review under 35 U.S.C. § 134(a) of the Examiner’s final rejections of claims 1-18. We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM.2 1 Real Party in Interest is Taiwan Semiconductor Manufacturing Co., Ltd. Appeal 2010-011760 Application 11/688,692 2 STATEMENT OF THE CASE Appellants’ Invention Appellants’ invention relates to an integrated circuit (IC) design method utilizing a virtual chemical mechanical polishing (CMP) process and resistance/capacitance (RC) extraction tool integrated to guide an IC design for accurate parasitic RC extraction and enhanced, efficient IC design. See Appellants’ Spec. ¶¶[0019], [0046], FIG. 2 and Abstract. Claims on Appeal Claims 1, 5, and 14 are the independent claims on appeal. Claim 1 is illustrative of Appellants’ invention, and is reproduced below with disputed limitations emphasized: 1. An integrated circuit (IC) design method, comprising: providing a design layout defined in a plurality of grids; simulating a chemical mechanical polishing (CMP) process to an IC substrate with a patterned structure defined by the design layout, the simulation generating a dielectric thickness and a metal thickness on at least one of the plurality of grids using an absolute reference, wherein the simulating the CMP process includes simulating the CMP process in a multilayer mode in which multiple layers are collectively considered in simulating the CMP process; 2 Our decision refers to Appellants’ Appeal Brief filed April 12, 2010 (“App. Br.”); Reply Brief filed August 16, 2010 (“Reply Br.”); Examiner’s Answer mailed July 6, 2010 (“Ans.”); and the original Specification filed March 20, 2007 (“Spec.”). Appeal 2010-011760 Application 11/688,692 3 extracting a capacitance based on the dielectric thickness on the at least one of the plurality of grids; extracting a resistance based on the metal thickness on the at least one of the plurality of grids; adjusting the design layout based on the extracted capacitance and resistance; forming a patterned material layer on a semiconductor wafer based on the adjusted design layout; and performing a CMP process to the patterned material layer on the semiconductor wafer. Evidence Considered The prior art relied upon by the Examiner in rejecting the claims on appeal is: Smith US 2005/0132306 A1 Jun. 16, 2005 Hong US 2007/0111504 A1 May 17, 2007 (filed Dec. 30, 2005) Examiner’s Rejection (1) Claims 1-5 and 7-18 stand rejected under 35 U.S.C. § 102(e) as being anticipated by Smith. Ans. 3-16. (2) Claim 6 stands rejected under 35 U.S.C. § 103(a) as being unpatentable over Smith and Hong. Ans. 16. Issues on Appeal Under § 102(e), whether the Examiner erred in rejecting claims 1-5 and 7-18 as being anticipated by Smith. In particular, the issue turns on whether Smith discloses: Appeal 2010-011760 Application 11/688,692 4 (1) “generating a dielectric thickness and a metal thickness on at least one of the plurality of grids using an absolute reference” as recited in independent claim 1 (App. Br. 18-19); and (2) “defining an absolute reference to a material layer and multiple layers underlying the material layer in a substrate … predicting a height of the material layer relative to the absolute reference” and “simulating the multiple layers incorporating a stacking effect” as recited in independent claim 5, and similarly recited in independent claim 14 (App. Br. 12- 19). Under § 103(a), whether the Examiner erred in rejecting claim 6 as being obvious over Smith and Hong. In particular, the issue turns on whether the combination of Smith and Hong discloses or suggests “the absolute reference [is] defined as an etch stop layer disposed in a first metal structure” (App. Br. 20-21). ANALYSIS We have thoroughly reviewed the Examiner’s rejection and each of Appellants’ arguments that the Examiner has erred. However, we are in full agreement with the Examiner that the claimed subject matter is unpatentable over the cited prior art. As such, we adopt as our own (1) the findings and reasons set forth by the Examiner in the action from which this appeal is taken and (2) the detailed findings and reasons set forth by the Examiner in the Examiner’s Answer in response to Appellants’ Appeal Brief. We further highlight and address specific findings and arguments for emphasis as follows. Appeal 2010-011760 Application 11/688,692 5 §102(e) Rejection of Claims 1-5 and 7-18 With respect to independent claim 1, Appellants contend that Smith does not disclose “generating a dielectric thickness and a metal thickness on at least one of the plurality of grids using an absolute reference.” App. Br. 18 (emphasis added). In particular, Appellants acknowledge that Smith discloses measurement of a dielectric thickness and a metal thickness. Id. Appellants acknowledge that the measurement of such a dielectric thickness and a metal thickness is based on a relative reference. Reply Br. 6. However, Appellants argue that Smith is silent regarding the use of “an absolute reference.” Id. In response, the Examiner takes the position that measurement of a thickness as disclosed by Smith requires taking measurement between two measurement points (i.e., a particular start point and a particular end point) in order to conclude the value of a thickness. Ans. 18 (citing Smith, ¶¶[0291], [0483], [0518], and FIG. 7). As such, the Examiner broadly interprets the term “absolute reference” as encompassing any reference including input layout used to measure a dielectric thickness and a metal thickness as disclosed by Smith. Ans. 19-21. We find the Examiner’s interpretation reasonable and not inconsistent with Appellants’ Specification. At the outset, we note that claims are given their broadest reasonable construction consistent with the specification. In re Am. Acad. of Sci. Tech Ctr., 367 F.3d 1359, 1369, (Fed. Cir. 2004). In the context of Appellants’ Specification, we note that Appellants’ Specification does not provide an explicit definition for the term “absolute reference.” Instead, Appellants’ Specification simply suggests one possible definition of Appeal 2010-011760 Application 11/688,692 6 the term “absolute reference” as “an etch stop layer disposed in a first metal structure” as shown in FIG. 6. In particular, Appellants’ Specification describes: The generating of the dielectric thickness and the metal thickness may include utilizing the dielectric surface height and the metal surface height. The simulating of the CMP process may include defining a height of the trench bottom relative to an absolute reference. The absolute reference may be defined as an etch stop layer disposed in a first metal structure. The generating of the dielectric thickness and the metal thickness may include utilizing the dielectric surface height, the metal surface height, and the height of the trench bottom in a multilayer mode. Specification, ¶[0045] (emphasis added). In the absence of an explicit definition for the term “absolute reference” from Appellants’ Specification, we find no error in the Examiner’s interpretation and, therefore, sustain the Examiner’s anticipation rejection of independent claim 1 and its dependent claims 2-4, which were not separately argued. With respect to independent claim 5 and similarly, independent claim 14, Appellants contend that Smith does not disclose “defining an absolute reference to a material layer and multiple layers underlying the material layer in a substrate … predicting a height of the material layer relative to the absolute reference.” App. Br. 12-19 (emphasis added). In particular, Appellants make several arguments against Smith, including: (1) Smith is silent as to whether a single reference can be used to calculate the thickness or height of multiple layers, and the claimed “absolute reference” that serves as a single reference point for multiple layers (App. Br. 14); Appeal 2010-011760 Application 11/688,692 7 (2) there is no extrinsic evidence to show that an absolute reference is necessarily present in Smith (App. Br. 16); (3) the plain meaning of the recited “absolute reference” in claim 5 should be interpreted as a reference from which respective heights of the “material layer” and the “multiple layers underlying the material layer” can be measured, rather than being interpreted to mean “a rule for measurement or a way to measure or guideline for measurement” (App. Br. 16); and (4) Appellants’ claim 5 involves a common “absolute reference” for multiple layers, and is not the same as measuring the thickness of any individual layer (Reply Br. 6-8). However, we are not persuaded by Appellants’ arguments and do not find reversible error in the Examiner’s position. See In re Jung, 637 F.3d 1356, 1365 (Fed. Cir. 2011). First, Appellants’ arguments regarding the claimed “absolute reference” as a single reference point or a common reference for (measurement) multiple layers are not commensurate with the limitations of Appellants’ claim 5. Neither a single reference point for multiple layers nor a common reference from which respective heights of multiple layers is recited in Appellants’ claim 5. Instead, Appellants’ claim 5 simply requires “predicting a height of the material layer relative to the absolute reference.” As such, we decline to read the argued limitations into the claims. Second, as previously discussed, the term “absolute reference” is not clearly defined in Appellants’ Specification. The Examiner has interpreted the term “absolute reference” as encompassing any reference including input layout used to measure a dielectric thickness and a metal thickness as disclosed by Smith. Ans. 19-20 (citing Smith, ¶¶[0291], [0483], [0518], and Appeal 2010-011760 Application 11/688,692 8 FIG. 7). We find the Examiner’s interpretation reasonable and not inconsistent with Appellants’ Specification, particularly in the context of FIG. 6 and FIG. 7. Next, Appellants contend that Smith does not disclose “simulating the multiple layers incorporating a stacking effect.” App. Br. 17 (emphasis added). In particular, Appellants argue that the stacking effect is shown in FIG. 5 and FIG. 6 and described as an “uneven topography” that passes from an underlying layer to an overlying layer, and is accumulated and passed to higher layer. App. Br. 18 (citing Appellants’ Specification, ¶[0026]). In contrast, according to Appellants, Smith does not disclose any “uneven topography.” Id. In response, the Examiner finds Smith discloses models of chemical mechanical polishing (CMP) are used to characterize multi-level effects between adjacent interconnect levels, and such multi-level effects of interaction between layers/levels are equivalent to the claimed “stacking effect” as recited in Appellants’ claims 5 and 14. Ans. 28-29 (citing Smith, ¶[0383]). We find no error in the Examiner’s findings as whenever multiple layers are created or simulated, “uneven topography” would be generated on a substrate and, as a result, a “stacking effect” would be incorporated. Appellants have not presented sufficient evidence or arguments to persuade us of reversible error in the Examiner’s findings and interpretation. Absent such evidence or persuasive arguments, we do not find error in the Examiner’s position and, therefore, sustain the Examiner’s anticipation of independent claim 1 and similarly, independent claim 14, and their respective dependent claims 7-13 and 15-18, which were not separately argued. Appeal 2010-011760 Application 11/688,692 9 §103 Rejection of Claim 6 Appellants contend that neither Smith nor Hong provides a definition of the term “absolute reference” as “an etch stop layer disposed in a first metal structure.” App. Br. 20-21. In particular, Appellants acknowledge that Hong discloses formation of a first or a second etch stop layer, but argue that: (1) Hong is silent as to whether the first or second etch stop layer can be used as an “absolute reference” to measure a film thickness as disclosed by Smith (App. Br. 20), and (2) even if an etch stop layer is used as a reference to measure a thickness, such an etch stop layer cannot be used to measure the thicknesses of other layers (Reply Br. 13). We disagree. A person of ordinary skill is also a person of ordinary creativity, not an automaton. See KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007). Using an etch stop layer as a reference point to measure a film thickness requires nothing more than the use of ordinary skill and common sense. As correctly noted by the Examiner, Hong discloses the use of an etch stop layer 215a, shown in FIG. 3A, to prevent a first metal line 220 from being over-etched in forming a via hole through an etching process. Ans. 30 (citing Hong, ¶[0049] and FIG. 3A). In considering Hong, it is proper to take into account not only specific teachings of Hong but also the inferences which one skilled in the art would reasonably be expected to draw therefrom. See In re Preda, 401 F.2d 825, 826-27 (CCPA 1968). One of ordinary skill in the art looking at Smith and Hong would certainly draw the inference that an etch stop layer 215a disposed in a metal layer structure, as shown in FIG. 3A of Hong, would be used in the context of simulation of Appeal 2010-011760 Application 11/688,692 10 Smith as a reference point to measure a film thickness of a single layer or multiple layers on a substrate. As such, we agree with the Examiner’s findings that the combination of Smith and Hong would teach or suggest the measurement of a metal thickness from an etch stop layer disposed in a metal layer structure. Ans. 31-32. Appellants also contend that Smith and Hong are not properly combinable because the Examiner’s proposed combination would yield unpredictable result. Id. However, Appellants have not presented sufficient evidence or arguments to persuade us that the combination of Smith and Hong would be improper or would have been “uniquely challenging or difficult for one of ordinary skill in the art” or “represented an unobvious step over the prior art.” See Leapfrog Enters., Inc. v. Fisher-Price, Inc., 485 F.3d 1157, 1162 (Fed. Cir. 2007) (citing KSR, 550 U.S. at 418-19). Moreover, the Examiner finds, and we agree, that the result of such measurement using an etch stop layer disposed in a metal layer structure is predictable. Ans. 32. For these reasons, we do not find error in the Examiner’s position and, therefore, sustain the Examiner’s obviousness rejection of dependent claim 6. CONCLUSION On the record before us, we conclude that the Examiner has not erred in rejecting claims 1-5 and 7-18 under 35 U.S.C. § 102(e) and claim 6 under 35 U.S.C. § 103(a). Appeal 2010-011760 Application 11/688,692 11 DECISION As such, we AFFIRM the Examiner’s final rejections of claims 1-18. No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv). AFFIRMED tj